Door switch for burglar alarm systems



P 1950 T. J. GUNDLACH 2,521,005

DOOR SWITCH FOR BURGLAR ALARM SYSTEMS Filed April 8, 1947 4 Sheets-Sheetl I'w I Fig. '6.

Fig. 7.

Inventor Theodore J; Gundlach v I o I W. N I

I, ttorneys Sept. 5, 1950 T. J. GUNDLACH DOOR SWITCH FOR BURGLAR ALARMSYSTEMS 4 Sheets-Sheet 2 Filed April 8, 1947 Inventor Theodore J.Gundlach Sept. 5, 1950 T. J. GUNDLACH DOOR SWITCH FOR BURGLAR ALARMSYSTEMS 4 Sheets-Sheet 5 Filed April 8, 1947 m m m h m I m U G J. e m d0 m T Q A A 1 m t m ow Qmwm n .L KN B mm 9 .8 F w m\ m w m A AIYQM. NMMN Q- Q vw. .NN wn mnfiYf Sept. 5, 1950 T. J. GUNDLACH 2,521,005

I DOOR SWITCH F OR BURGLAR ALARM SYSTEMS Filed April 8, 1947- 4Sheets-Sheet 4 Fig. I5.

290 30a 28a 26b Int-'Entor Theodore J. Gund/ach a Attorneys PatentedSept. 5, 1950 UNITED STATES PATENT OFFICE DOOR SWITCH FOR BURGLAR ALARMSYSTE This invention relates to a burglar alarm system for homes,adapted to sound an alarm to indicate the opening of a door or window,when unwarranted entrance is being made.

An object of the invention is to provide a burglar system which can beoperated either on a battery, orfrom the wiring circuit of a house orbuilding by the use of a transformer. Preferably a six volt dry cellbattery or a six volt transformer reducing the line voltage of the housewiring to six volts, is used.

Another object of the invention is to provide novel door and windowswitches, normally open, when the doors and windows are closed, butadapted to close, upon the opening of the doors or windows, the circuitof an electro-magnetic device, operating an alarm circuit.

Another object of the invention is to provide a door switch, which canbe readily applied to a door jamb in a horizontal or vertical positionand which comprises contacts normally open and held by a plunger whichreleases the switch when the door is opened.

Another object of the invention is to provide a switch adapted forapplication to a window sill, and normally held open by means arrangedon a window sash when the window is closed, but closed upon the openingof the window, said switch when energized, closing an alarm circuit.

Another object of the invention is to provide switches for controllingthe circuits including the door and window switches and the magneticallyoperated switch said switches being manually operated to render thealarm circuit inoperative when it is not desired to operate the alarm,and to open the alarm circuit after the alarm has sounded, so thatcontinued operation thereof will be prevented.

A still further object of the invention is to provide an alarm systemfor doors and windows which will not operate until they are actuallyopened and which provides for momentarily operating a magnetic switchcircuit in order to close a circuit to an alarm, whereby the drain onthe holes to be drilled into the door jamb, which does not need anelectrical certificate or to be approved by fire underwriters, whichrequires no electrical knowledge to install and which oper ates on aminimum of electrical current, and which can be controlled by manuallyoperated knife switches at convenient points, in addition to beingeconomical to manufacture and install.

Other objects and advantages reside in the details of construction andoperation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming part hereof, wherein likenumerals refer to like parts throughout, and in which:

Figure 1 is a diagrammatic view of an alarm system constructed inaccordance with the invention. as applied to a door and a window.

Figure 2 is a sectional elevation, showing the door operated switchapplied to a door jamb .or frame and door.

Figure 3 is a sectional elevation showing a magnetically operated switchcontrolled by the door switch for closing a circuit to an alarm.

Figure 4 is a sectional view taken on the line 4--4 of Figure 3.

Figure 5 is an enlarged sectionalview taken on the lines 55 of Figures 3and 4.

Figure 6 is a view similar to Figure 2 but showing the switch thereof inposition when the same is set with the door closed.

Figure 'I is a view similar to Figure 6, but show ing the switch closedwhen the door is opened.

Figure 8 is a sectional view taken on the line 8-8 of Figure 2 but withthe door closed.

Figure 9 is a sectional view taken on the line 99 of Figure .2.

Figure 10 is an elevation showing a window switch applied to a windowframe and sash at the sill of the window with the switch open when thewindow is closed.

Figure 11 is a sectional elevation taken on the line i I--| l of Figure10.

Figure 12 is an elevation of the casing of the switch shown in Figure 2.

Figure 13 is an enlarged bottom view showin the means for setting theswitch shown in Figure 2.

Figure 14 is a sectional view taken on the line -14 of Figure 9.

Figure 15 is an elevation partly in section of a door operated switchadapted for doors opening inwardly and showing the switch closed whenthe door is open.

Figure 16 is a sectional view taken on the line l6-l6 of Figure 17 withthe switch set as in Figure 2 when the door is closed.

zontally in a door frame or jamb [I so as to be engaged by the door !2when closed and released when the same is opened. For this reason, theswitch I!) comprises a casing or base l3 of suitable configuration tohouse the mechanism which is attached to the door frame or jamb as at Mby screws or the like so as to be easily installed, without drillingholes in the door jamb or special equipment and provided with aremovable cover plate I 5. The end toward the door l2 has a reducedtapered neck portion l6 terminating in a cylindrical portion H, in whicha bearing collar i8 is mounted to slidably receive a plunger IS, theprojecting end of which is adapted to be engaged by the face of the doorl2 near its free edge usually equipped with a lock and door knobs andopening outwardly. The bearing sleeve or collar I8 is provided at theouter end of a base plate 25 detachably mounted at the base of thecasing 13 a indicated at 2| or directly mounted thereon if desired. Theplunger has its inner end movable in a bearing sleeve 22 on the'base orattaching plate 20, and the plungeris normally projected or heldoutwardly by a biasing or expansible coil spring 23 mounted onthe'plunger l9 between the sleeve of collar 22 and a, stop or washer 24forming an enlargement on the plunger held by a cotter pin 25 orotherwise, so that the plunger is held outward toward the sleeve l8 butadapted to be pressed inwardly to its retracted position by'the doorwhen closed. The base or casing I 3 may have the bottom thereof ofinsulating material or include an attaching plate 26 of such materialdetachably secured therein and mounting a switch including a bracket 21similar to that used on magnetic relays or telephone switches having abifurcated end 28 with spaced laterally bent lugs. 29 in and beneathwhich an armature-like plate 30 is fulcrumed at a reduced. portionformed by opposite edge recesses 3! at the bifurcation 26 formingoutwardly extending lugs 32 engaging beneath the lugs 29 and heldoutward by a spring 33 anchored as at 34. The plate 30 has a reducedportion 35 with an adjacent right angularly bent portion 36 forming astop shoulder for engagement through an opening 31 in a lever 38 havinga reduced free end and a reduced inner portion 39 at one side as seen inFigure 9 beyond which its normal widened portion is provided withlateral pivot ears 40 fulcrumed on a pivot pin 4| held in apertured ears42 of the bracket 21 attached to plate 26 as at 43. One of the ears 40is formed with an arm 44 having a lateral pin 45 bearing an insulatingroller 46 and inwardly thereof, with a lateral arm 41 extending throughan arcuate slot 48 in the cover plate I 5 to set the lever 38 and arm 44so that the edge of the opening 31 will engage the shoulder 36 as willbe later described. This may be done with the cover plate l5 in positionsecured as at 49 to the open side of the casing l3 which may be anchoredon a baseboard 50 attached to the door jamb of the frame The arm 44 isrigid with and extends at an acute angle to the lever 38 and isresiliently held over the reduced portion 5| of the plate 30 to engageeither the shoulder 36 or shoulders 52 formed by the reduced portion 5|,by means of a coil spring 53 on the pivot pin 4| with the ends thereofbearing against the bracket 27 and the inside of the lever 38. A pair ofspring contacts 54 and 55 are mounted in normally spaced relationbetween insulating or fiber blocks 56 attached to the bracket 21 andconnected in circuit as will be later defined.

The system also includes an electro-magnetic switch 51 shown in Figure 1and Figures 3, 4 and 5. The electro-magnetic switch 5'! is placed at anyconvenient position in a house or building away from a door or window inconnection with which the system works. It comprises a casing 58suitably anchored and having a cover plate 59 detachably secured inposition and has a bracket 21 secured therein as at 60, the bracket 2'lcorresponding to the bracket 2'! except that one end 6| instead ofextending parallel to the opposite end, extends at right angles theretoand is offset from the attaching portion and parallel thereto. A similarplate 30 is fulcrumed to the adjacent end of the bracket as described inconnection with Figure 2 and cooperates under pressure of a spring 33with a similar lever 38 except that the reduced portion 39 and recessextending into one side of edge to accommodate the resilient switchcontacts 54 and 55 as shown in Figure 9 of the switch I0 is omitted.Lever 38 has the arm 44 and is similarly spring-pressed to cooperatewith the plate 30, which in this instance forms an armature forattraction by the core of an electro-magnet 62 mounted on thecorrespondingly ofl'set portion of the bracket 21' opposite the portion6|. A pair of normally separated spring contacts 63 and 64 are mountedin spaced relation between fiber blocks 65 of insulating 'materialsecured to the portion 6|. Spring contact 64 is engaged by the roller 56of the arm 44 when the arm 38' is held by the shoulder 36 of thearmature plate 30. Another pair of similar mounted contacts 66 and 6!are also mounted in normally separated relation between the fiber blocks65 to be moved in contact by engagement with the roller 46 of the arm 44when the lever 38' is released from the shoulder 36 by attraction of thearmature 30 to the core of the magnet 62 upon energization of the coilthereof. The lever 38' is adapted to be manually moved and set togetherwith the arm 44 as is the lever and arm of Figure 2, as shown anddescribed in connection with Figures 12 and 13 of the drawings.

In Figures 10 and 11 of the drawings, a switch is shown for employmentin connection with win- 0 dows in which 68 is the frame in which a lowersash 63 is movable or slidable and mounted on the same, is an anglebracket 10 secured in position in any suitable manner as byscrews H. Theoutstanding portion of the bracket 10 is provided with an elongatedvertical slot 12 to which an insulation plate 13 having a tapered bottomedge 14 is adjustably bolted as at 15 so as to be capable of verticaladjustment to properly co-operate with the spaced contacts 76 and 11 an-70 chored to an insulation block 18 mounted on a sill 7 window sash israised the tapered lower edge 14 of the insulation plate 13 moves out ofthe space between the contacts 16 and 11 and permits them to springtogether; whereas when the sash is closed, said tapered edge will forcethe contacts 76 and i1 apart to open the normally closed circuittherethrough.

The switch elements or units and cooperating parts are duplicated foreach door and window or a house or building and the alarm system toprevent unwarranted entrance or burglary, is set in an electricalcircuit as shown in Figure l of the drawings, in which a source ofelectrical energy which may be a six volt dry cell battery 82, isconnected in circuit at its positive or feed side through a conductor 83with an interposed knife switch 84 or other form of control switch forthe circuit to the contact 54 of the door switch unit ill. Of course, asix volt transformer such as used on bells or signals may be connectedto the house wiring as a substitute for the battery. The contact 55 isconnected by a conductor 85 to one terminal of the coil of theelectro-magnet 62, the other terminal or end of which is connected by aconductor 85 to the contact 63 of the electromagnetic switch 5'!positioned at any convenient place desired in a home or building. Theother contact 64 cooperating with the contact 63 is connected by areturn wire or conductor 8'! to the other terminal of the battery ortransformer, such as the negative pole. The conductor 83 through abranch wire, also connects to the contact fit of the electro-magneticswitch element 5! with an interposed control or knife switch 88 and thecontact 5! is connected by a wire or conductor 89 with a suitable alarm,such as a bell, 98 with the return through the wire Bl to the negativepole of the battery or transformer. The conductor 85 also leads to thecontact 16 of thewindow switch, with the return from the contact T!through a conductor 9i, through an interposed knife or other switch 82,to the conductor 83 which supplies current to said switch. The contactit is thus connected through the conductor 85 to the electro-rnagnet 52.Thus, in the operation of the system, the door 52 is opened until theplunger I9 is pushed back by the spring 23, the lever 38 of the doorswitch unit Iii is then moved over until it engages behind the shoulder36 of the plate til and then the switch M is closed. The correspondinglever 38' of the electro-magnetic switch unit 57 is correspondinglymoved to engage behind the shoulder 38 of the armature plate 3E and thenthe switch it in the alarm or bell circuit is closed. Thus, when thedoor 12 is closed against the plunger I9 at the door frame or jarnb, itpushes the plunger in against the coil spring 23 to engage the inner endof the plunger with the plate i i! to swing the same inwardly againstthe spring 33 and unseat the shoulder 36 from the outer edge of theopening 31 in the lever 33, thus releasing the latter so that it willswing over the reduced portion of the plate 38 against the side of thebolt It as shown in Figure 6 of the drawings under the tension of thespring 53 while still maintaining the contacts 5 5 and 55 out ofengagement. Also, when the windows are closed, the sash 69 will move theplate 13 between the normally engaged contacts is and l! to electricallyseparate the latter. By holding or stopping the lever 38 against theinner side of the bolt E9, it will be prevented from going any furtherunless the door is opened. However, if the door is opened, the spring 23will force the bolt outwardly to release the lever 38 and permit thespring 53 to move the arm it against the contact 54 and move it intoengagement with the contact 55 as shown in Figure 7 of the drawings,when the lever 38 will move over the reduced portion 5! of the plate 30to engage the shoulders 52 where further movement of the lever isprevented. With contacts 54 and 55 engaged, the circuit from the batteryor transformer 82 with the switch 84 closed, is closed through theconductor 85 through the coil 62, conductor 86, contacts 53 and 64closed by setting the lever 38 of the electro magnetic switch unit 5?against the shoulder 3t of the armature plate 30 when set for operation,with the return through the conductor 87 to the source of electricalenergy. This momentarily energizes the magnet 62 to attract the armature36 thereof and release the lever 38 from the shoulder 36 so that itscorresponding arm M will move against the contact 61 and close the sameagainst the contact 66 while at the same time releasing the contact 64to separate from the contact 63 and open the magnetic circuit. The alarmor bell circuit will then be closed through the conductor 83, switch 88,contacts 56 and 67, conductor 89, alarm 96 and return conductor ill tothe source 82 to sound the alarm, which can be out 01f at the switch 88at a convenient place. The same operation takes place when the window israised to raise the plate 53 and permit the contacts 16 and H to engageto momentarily energize the electromagnet 62 with the same result aswhen the door It is opened, except that in this case, the circuit to themagnet 52 is closed through the conductors 83, 9! and 85 through theswitch 92 momentarily, to close the alarm or hell circuit at thecontacts 66 and 51 as previously described. To again reset the system,the switches 85 and 92 are opened as well as the switch 83 and theswitch units reset as previously described.

Thus, it will be seen that the door or window, of which there may be anynumber connected in the circuit, must be opened before the alarm will goofi, but once the alarm sounds, it cannot be shut off by closing a dooror window but only by opening the knife switch 88. in the alarm circuitwhich will be at some convenient point for the operator distant from thewindows and doors. When the switch units at the doors or windows areclosed, the circuit to the electro-magnet 62 is only momentarily closedto close the alarm circuit only for such period that it is permitted tooperate and until the switch 88 is opened, thus economizing in the useof current. The device is also easy to install without requiring specialpreparation or fittings, does not need an electrical certificate orapproval by fire underwriters and no special electrical knowledge inorder to install the same. Obviously, the door switch can be placedhorizontally or vertically on a door jamb and is in one complete unit soas to fit any door opening outwardly, as described above, or for doorsopening inwardly as hereinafter described. In Figures 15 to 20inclusive, I have shown the switch adapted for use in connection withdoors opening inwardly in connection with the system and circuit asshown in Figure 1 together with the magnetically operated switch asshown in Figure 3. In this form, the circuit closer or switch i0 isadapted to be mounted vertically or horizontally on the inside of a doorframe or jamb l I, with which the door l2 cooperates.

In this form, it comprises a casing or base frame [3a connected at oneside by an angular bracket or attaching portion 260, secured to the doorframe or jamb detachably as shown at the side or top. In case the frameis mounted at the side of the door opening, the top is mounted by meansof a bracket 26b having an elongated slot 23a through which a clampingscrew 29a carried by the frame I3a is extended and adjustably held by anut 39a with a sliding adjustment to allow for any deviation on thesurface of the door frame. The device embodies a similar bracket 210.having a bifurcated end 28 with spaced laterally bent lugs 29 in andbeneath which an armature like plate 39 is fulcrumed at a reducedportion formed by opposite edge recesses 3I at the bifurcation 28forming outwardly extending lugs 32 engaging beneath the lugs 29 andheld upward by a spring 33 anchored as at 34. This switch also embodiesthe parts 35 to 56 inclusive as described in connection with Figures 1,2, 6 and 7, as well as Figure 14 and corresponding parts of themagnetically operated switch or unit 51 as described in connection withFigures 3, 4 and of the drawings and specifically, the structure shownin Figure 9 with respect to the switch proper. However, in order to settheplate and the lever 38 as previously described, without the use of abolt I9 adapted for doors opening outwardly, so that the right angularlybent portion 36 at the end will engage the opening 31 to form a stopshoulder in the lever 38 and release the same when the door is openedinwardly, a lever 93 is pivoted at cars 94 to the bight portion of aU-shaped support 95 mounted on the side of the frame I3a toward the doorand has a spring 96 on the pivot forming portion 95 with one end engagedagainst the frame I30. and the other against the lever 93 to hold thelatter in the position shown in Figure 1'7 of the drawings against alimiting member 97 also of U-shaped form disposed at right angles to thepivot member 95. The adjacent end of the lever 93 has an inward angularprojection 98 disposed toengage the plate 38 so that when the lever 38is set behind the shoulder 36 at the opening 31 in the manner shown inFigure 18 of the drawings, the arm 44 will be swung over to permit thecontacts 54 and 55 to separate from the normally engaged or contactingpositions shown in Figure 15. To permit this, the plate 30 may swingoutwardly under the action of the spring 33 by moving the lever 38 overthe shoulder 36 by means of an extension 99 projecting laterally fromthe free end of said lever. The lever 93 engages the bight of thelimiting member 91 in its normal position but the extension 98 isadapted to be moved inwardly to engage and depress the plate 39 so as torelease the shoulder 36 from the edge of the opening 31 in the lever 38and permit the lever under the action of its spring 53 to movedownwardly over the reduced end of the lever 38.

In order to actuate the lever 93 by closing the door I2, the latter isprovided with a bracket I90 having a threaded socket mounting a screwstud IllI which is held by a nut I92, the stud being in the form of abolt havin its head set behind the aperture of the bracket through whichthe stud or bolt extends. An angular arm I03 has a head I9 5 providedwith a threaded aperture adjustably mounting it on the stud or bolt IUIand is adapted to be held in adjusted position by means of a binding nutI95 so that when the door is closed, the arm I93 will engage the freeend of the lever 93 and unseat the lever 38 from the shoulder 36 so thatthe lever 38 will be released therefrom and move against the end 98 asshown in Figure 8 of the drawings, in which position it willbe held aslong as the door remains closed and until the same is opened inwardly.When this occurs,

the arm I03 will be released from its pressure against the free or innerend of the lever 93, which will swing inwardly at its free end, therebymoving the extension 98 outwardly to permit the lever 38 to be releasedand dropped down on the reduced inner end 5I and against the shoulders52 so that the contacts 54 and 55 will engage as shown in Figure 15 andclose the circuit to the electro-magnetic switch 51 and consequently tothe alarm 90 through the source of electrical current to sound the alarmas previously described in connection with the switch unit III.

Thus, there is comprehended within the scope of the invention, a devicefor use in connection with doors opening both outwardly and inwardly,together with means for setting the switch in position to operate whenthe door is closed and adapted to be released for closing the circuitwhen the door is opened. While the device is shown on a door either atone side or at the top with the frame I3a arranged vertically orhorizontally, it is to be understood that the same may be positioned asdesired and that the frame or casing I3a may be entirely closed exceptat the side toward the door in connection with which the lever 93 ismounted, so as to enclose the parts therein with the conductors 83 and85 extending therefrom and controlled by the knife switch 84 asheretofore described. The adjustable lever on the door will alsocompensate for difierent thicknesses of the door and the device can beset to operate on doors swinging in either direction, that is right orleft hand doors.

While in the foregoing there has been shown and described the preferredembodiment of this invention it is to be understood that minor changesin the details of construction, combination and arrangement of parts maybe resorted to without departing from the spirit and scope of theinvention as claimed.

What I claim as new is:

1. In a burglar alarm, an actuation device comprising a hollow casingadapted to be secured to a door frame, said casing having a neckportion, a bearing collar mounted in said neck portion, said bearingcollar having a plunger slidably mounted therein, the outer end portionof said plunger projecting beyond the neck portion of the casing, theinner end of said plunger being supported by and movable in a bearingsleeve, said bearing sleeve being carried by an attaching plate,resilient means urging said plunger outward of said casing; an insulatedbracket mounted on said casing, a member fulcrumed on said bracket, alever having two legs bent at an acute angle fulcrumed on a pivot pincarried by said bracket, said lever having an aperture therein, saidmember extending through said aperture and engaging said lever, aninsulating roller pivotally secured to the second leg of said lever, acoil spring on said pivot pin having its ends respectively bearingagainst said bracket and said first leg of said lever; said bracketshaving insulating blocks attached thereto, and a pair of spring contactsmounted in normally spaced relation between said insulating blocks, saidspring contacts being actuated into closed relationship by said plungeractuating said member which in turn actuates said lever which pressessaid contacts together.

2. The structure of claim 1 wherein said resilient means comprises acoil spring, said plunger having stop means adjacent its outer end, saidcoil spring biasing said bearing sleeve and said stop means.

3. In a burglar alarm system, a contact making device, said deviceincluding a contact operating arm, a pivotally mounted spring pressedmember connected with said arm and provided with an opening, a springtensioned member with a restricted tongue portion projecting throughsaid. opening of the first member and provided with a step and withshoulders, said first.member being adapted to be held by the step of thesecond member upon manual setting of the two members forinterengagement, but snapping back along the restricted portion of thesecond member to the shoulders upon release thus moving said contactoperating arm into its final contact position.

4. In a burglar alarm system, an actuation device comprising a dooroperated reciprocating member, a pivotally mounted spring pressed memberprovided with a restricted tongue portion and with a step and shouldersadapted to cooperate with said door operated reciprocating member, aspring tensioned member with an opening, said spring pressed memberprojecting through said opening of said spring tensioned member, saidspring tensioned member adapted to be held by the step of the springpressed member upon setting of the two members for inteengagement, butsnapping back along the restricted portion of the spring pressed memberto the shoulders upon actuation by said door operated reciprocatingmember upon closing of the door subsequent to the setting, thus movingsaid spring tensioned member into a trigger position conditioned toclose an alarm circuit upon opening of the door.

5. The actuation device of claim 4 wherein said door operatedreciprocating member comprises a spring pressed rod adapted to projectfrom the door jamb and adapted to be moved by the door panel into aretracted position, said position releasing said spring tensioned memberfrom its engagement with the step of the spring pressed member yetholding said spring tensioned member so as to prevent it from snappingback as long as the door is closed, said reciprocating member moving outof engagement with said projection upon opening of the door.

THEODORE J. GUNDLACH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 225,606 Houpt Mar. 16, 1880492,478 Sturts Feb. 28, 1893 942,964 Juruick Dec. 14, 1909 1,059,007Sharp Apr. 15, 1913 1,098,362 Nelson May 26, 1914 1,115,720 Munsell Nov.3, 1914 1,372,437 Koch Mar. 22, 1921 1,497,241 MacGonigal et a1. June10, 1924 1,997,155 Sprecker Apr. 9, 1935

